Your guide to Begonias
​
What is a begonia?
Begonias are a genus of plants with over 2000 species and many more cultivars, registered hybrids and unidentified species.
Begonias can be roughly grouped into different types based upon growth habbts and cultivation requirements but these groups are very loose and there are many crossovers, and hybrids with some begonias belonging to more than one group.
Wax or Bedding Begonias
These are compact, bushy, mounded, fibrous-rooted plants that feature fleshy stems, waxy dark green to bronze leaves and loose clusters of single or double flowers. Although cultivated extensively as a warm season annual, wax begonias can be grown indoors as a perennial plant. Propagation is from seed.
Tuberous Begonias
Cultivars which are usually derived from Begonia × tuberhybrida. Originating from mountainous areas of South America, these begonias require cooler conditions. They produce spectacular flowers and are dormant in winter.
Cane Begonias
Cane begonias come in a range of shapes and sizes but can be identified by their bamboo like stems and angel wing like leaves. Generally they are tough and can be grown indoor in cooler areas or outdoor as a garden plant in warmer areas. They respond well to pruning and are easily strike from cuttings.
Rhizomatous begonias and Rex begonias
These plants have a fleshy rhizome from which the leaves arise. Begonia rex is a rhizomatous species from which numerous hybrids have been produced for their spectacular foliage. Rhizomatous begonias are easily propagated by leaf cuttings and readily produce seed.
Trailing Begonias
Trailing - scandent begonias like to scramble, climb and sprawl. They are ideal for hanging baskets where their foliage and flowers can be seen to best advantage. Trailing begonias are easily prorated from stem cuttings.
Shrub Begonias
Shrub begonias are more compact and bushy than cane begonias and make great garden specimens.
Terrarium Begonias
Terrarium begonias are the true tropical begonias that require an equatorial climate year round. Constant moisture, even temperature and high humidity are essential in cultivation. Unless you live in a tropical rainforest, then these species are best kept in a simulated environment.
BEGONIA CULTIVATION
Begonias grow from temperate to tropical climates with the vast majority of species being from tropical and sub tropical climates. Apart from a few exemptions most begonias require even temperatures, humidity, good air circulation and a well drained potting medium. Begonias will not tolerate wet feet and soggy potting mediums. They require bright indirect light
Begonias will quickly rot if given too much moisture and quickly dry out with out enough humidity. It can be a tricky balance. Finding the right species for the right situation is important.
Begonias will grow happily as indoor plants and terrarium plants if their conditions are met.
Their soil should be allowed to dry out between waterings. Begonias are similar to succulents in that requirement. It is important to keep up humidity between waterings which can be achieved through a light mist in the mornings. Keep your begonias away from direct sunlight and hot windows as their delicate foliage can burn easily.
My go to potting medium is a 50/50 mix of a good quality potting mix and perlite with commercial quality slow release fertiliser added to the mix at the manufacturers recommendation. Soil Ph is best kept neutral to slightly acidic but some species will require more specific Ph modifications so it is best to do research on individual species.
Begonias respond well to foliar and liquid feeding with seaweed and fish based solutions. Apply as to the manufacturers instructions. Begonias always respond well to being repotted and divided which should be done at least every 12 months.
Airflow is crucial to good cultivation. Consider placing your begonias in a situation where they receive some air movement and terrariums may need a small fan.
If you get the cultivation spot on then begonias are relatively pest free plants. If you notice signs of fungal disease then have a look at your watering schedule and your airflow. Mancozeb is useful agains stubborn fungal issues. Pests are similar to those that plague other indoor plants and are best treated early on to avoid infestations.
Propagating begonias.
Begonias can be propagated in a number of ways.
Cuttings - leaf and stem cuttings are both acceptable with stem cuttings being preferred for the cane, shrub and trailing types and leaf cuttings preferred for the Rhizomatous. Tuberous begonias can be divided in their dormant stages.
As with most plant probation, the use of sterile equipment and media will give better results. I prefer lidded plastic kitchen containers.
Containers should be sterilised by boiling in water for 5 minutes. A propagation mix of 50% moist coco peat and 50% vermiculate can be sterilised by placing into a metal baking tray, cover with foil and then bake at 180 degrees C. For 30 minutes. Allow to could completely before placing into the sterilised containers.
Begonias also grow readily form seed. The seed looks like a fine brown dust that can be evenly sprinkled across the same probation media as mentioned above, into a sterile container. Germination rates differ across species.
Creating and harvesting begonias seed is fun and easy. Begonia have male and female flowers occurring separately and often and different times, on the same plant. Mails flowers produce stamen and female flowers have an ovary with two to four stigmas. The trick is to place ripe pollen onto receptive stigmas. You will know if you have been successful as the ovary will swell up and slowly ripen. When it is ready for harvest it will naturally dry up and fall from the plant. Use a small pair of sterile scissors to cut open the dried ripened pod onto a tissue, releasing the dust like tissue. Use tweezers to remove any plant debris and pieces of the seed pod. Seed can be planted immediately or wrapped in the tissue, placed in a zip lock bag and stored in a cool dry place until you are ready to sow.